Rear-of-panel knife-blade switch



Feb. 19, 1929. 1,702,463

H. J. CRABBS REAR-OF PANEL KNIFE BLADE SWITCH Filed Jan. 20, 192.2 figl. 2/. /4

2 Sheets-Sheet 1 /4 INVENTOR ATTORN EY WITNESSES: g

Feb. 19, 1929.

H. J. CRABBS REAKOF-PANEL KNIFE BLADE swl'rca Filed Jan. 20.1922 2 Sheets-Sheet WM mm W NJ I ATTORNEY Patented Feb. 19, 1929.

UNITED STATES 1,702,463 PATENT VOFFICE.

HERBERT J. CRAFBBt OE PITTSBURGH, PENNSYLVANIA, ASSIGNOR T WESTINGHOUSE ELECTRIC & MANUFACTURING. COMPANY, A CO'KPGRAIIION OF PENNSYLVANIA.

REAR-OF-PANEL KNIFE-BLADE SWITCH.

Application filed January 20, 1922'.

My invention relates to knite switches. more especially to the rear-of-pancl-mounted type of switch in which the contact elements are remote from the operating side or active "tron t. 1

It is among the objects of this invention to provide a switch of the above designated type which, shall be simple to operate. which shall consist of a n'linimum number of parts. which shall be economical to manufacture and which shall be mechanically cfl icient.

In my co-pending application Serial No. 503,859. filed Sel'iteniber 28. 1921 for kn iteblade switches, is described a rear-ot-panelmounted knife switch of a. unitary structure which may be seemed as a unit to a switchboard panel. In my present invention I provide an improvement in. the mounting of the lever and in the sliding: engagement of the I lever with the switch-blade element which engages the contact members.

In the accompanying drawings constituting a part hereof, in which like reference characters designate like parts,

Figure 1 is a rear elevational View of a knife switch embodying my invention;

Fig. 2 is a side elevational view thereof, partially in section;

Fig. 3 is a plan View of a pivoting slide member for joining the lever with the contact elements;

Fig. 4 is a rear elevational view of a modification of the switch; and

Fig. 5 a side elevational view thereof, partially in section.

As shown in Figs. 1 to 3.1 provide a switch base 1 of suitable material. such as marble. slate or an insulating: composition. which is secured to a mounting bracket 2 and mounted on a switchboard panel by suitable screw bolts l which also support a. metal plate 5 which tunctitais as a lever step. A. plurality of contac; members 6 and binge jaws 7 are mounted on the base i. and the hinge jaws and contacts a re provided with lead terminals 8 and 9. respectively.

A plurality of knife-blade members 10 are pivotally mounted on the hinge jaws 7 and are provided with a plurality of auxiliary quick-break snap-switch members 11 and 12, cross-connected by a coil spring 13. The knife-switch members 10 are connected together by an insulating yoke 14 which is movably connected to an operating lever 15 by a pivoting member 16 mounted in the forked Serial No. 530,710.

end thereof. The member 16 consists of a metal rod having reduced end portions 17 pivotally supported in the forked end of the lever 15 and provided with cotter-pin openings 18' and a central opening 19 for engaging a stud member 20 which is secured to the yoke 14 by a serew-thread-and-unit combination 21.

The operating lever 15 is pivotally mounted on a supporting bracket 22 and is provided with a yield able contact lug 23 which is secured by coil springs 24 to provide a yielding support in the notched contact Slll'fttPQ 25 of the bracket 22. The lever 15 further provided with an insulating handle 26.

As shown in Figs. 4 and 5. the pivot-sliding joint connection between the operating lever and the movable contact or knife-blade members is provided. by suspending the member 16 from the insulating yoke 14 on a supportingbracket 27 secured to the yoke and by securing the stud member 20 on the end of the lever 15. This is just the reverse construction of the switch shown in Figs. 1 to 3 and functions in a similar manner. The leversupporting bracket 22 is provided with an angular plane faced contact surface 28 for engaging a yieldingly mounted pressure plate 29 and secured to the lever and supported by a spring" to maintain the lever 15 in either the closed or the open position.

The switch mechanism operates as follows The operating lever 15 is placed in a position perpendicular to the panel 3 holding the knife-blade members 10 in alignment therewith and disconnected from the contacts or switch jaws 6. The lever 15 is moved up or down into the positions shownin Fig. 2. the sliding-joint connection between the knifeblade members and the lever arm permitting a rotative movement of the member 16 and a simultaneous sliding of the stud member 20 in the opening 19 thereof. This motion provides an anti-frictional contact between the members to permit bringing" the switch blades 10 into contact with the jaws 6.

lVhen the switch is again opened, the auxiliary spring-actuated-break-switch member 11 maintains contact with the switch jaws 6 until the main knife-blade member 10 has swung clear and broken contact therewith. The tension of spring 13 is so adjusted that the blade member 11 will break contact at this point with such speed as to avoid fusion or burning caused by arcing produced by a slow breaking of the engagement of the knifeblade members and the corresponding stationary contact members.

From the above description of my invention, it will be readily understood that a double throw baclcof-board switch made in accordance therewith provides a simple and eflicient switch mechanism which is inexpensive to manufacture and simple and positive in its operation.

Although I have described a specific embodiment of my invention, it will be obvious to those skilled in the art that various modifications may be made in the details of construction thereof without departing from the principles herein set forth. For instance, the general details, such as switch aws, pivot supports, knife-blade terminal screws and the like, may be of any suitable. shape and design, the mounting brackets or switch base maybe designed to suit any specific application and the auxiliary switch jaws or the yielding support of the levers may be omit ted. These and various other changes in details of construct-ion may be made in my structure without departing from the spirit and scope of my invention.

I claim as my invention:

The combination with a switch panel, of a base adapted to be secured thereto, a plurality of contact members mounted on said base, some of said contact members being pivotally mounted and connected by an insulating yoke, a bracket for pivotally mounting an operating lever, and a member pivotally mounted on the end thereof, said memher having an opening for slidingly engaging a stud projecting from said insulating yoke.

In testimony whereof, I have hereunto subscribed my name this 10th day of January, 1922. e

HERBERT J. CRABBS. 

